Process for increasing the melt viscosity of polyamide with aryl phosphate compound

Abstract

A process for decreasing the melt index and increasing the viscosity of polyamide compositions by adding thereto an effective amount of an aryl phosphate compound, and thereafter heating the composition until the desired changes in melt index or viscosity are attained.

What is claimed is: 
     
       1. A process for decreasing the melt index and increasing the viscosity of a polyamide which comprises: A. forming a molten mixture of said polyamide and an effective amount of an aryl phosphate compound of the formula: ##STR5## (a) wherein R 1  is a substituted phenyl group of the formula: ##STR6##  wherein: X is the same or different at each occurrence and is such that the Hammett sigma (σ) values of X substituents is greater than zero; and n is an integer which is equal to or greater than 1; and   (b) R 2  and R 3  are the same or different and are individually hydrogen or R 1  ; and     B. Heating said mixture for a time and at a temperature sufficient to decrease the melt index and increase the viscosity of said polyamide.   
     
     
       2. A process according to claim 1 wherein R 1 , R 2  and R 3  are the same. 
     
     
       3. A process according to claim 1 wherein n is 1, 2 or 3. 
     
     
       4. A process according to claim 1 wherein n is 1 or 2, and X is substituted in the para position, meta position, or para and meta positions. 
     
     
       5. A process according to claim 3 or 4 wherein n is 1 or 2, and X is selected from the group consisting of nitro, cyano, alkylcarbonyl, trifluoromethyl, aldehyde, chloro, bromo and iodo. 
     
     
       6. A process according to claim 5 wherein X is chloro, bromo or iodo. 
     
     
       7. A process according to claim 6 wherein X is chloro. 
     
     
       8. A process according to claim 1 wherein said phosphate compound is tri-(p-chlorophenyl) phosphate. 
     
     
       9. A process according to claim 1 or 4 wherein said polyamide is polycaprolactam. 
     
     
       10. A process according to claim 1 wherein the amount of said aryl phosphate compound is at least about 0.05 weight percent based on the total weight of the mixture. 
     
     
       11. A process according to claim 9 wherein said amount is from about 0.1 to about 10 weight percent. 
     
     
       12. A process according to claim 10 wherein said amount is from about 0.2 to about 2 weight percent. 
     
     
       13. A process according to claim 10 wherein said amount is from about 0.1 to about 10 weight percent.